Sewing machine driving device



Aug. 25, 1936. w. H. BRADY, 2,052,125

SEWING MACHINE DRIVING DEVICE Filed April l5, 1935 2 SheelLS-Sheel'l 1,Lm e2 u 13 Au@ 25, 1936. w. H. BRADY 2,052,125

SEWING MACHINE DRIVING DEVICE Filed April 13, 1935 2 Sheets-Sheet 2Patented Aug. 25, 1936 PATENT OFFICE SEWING MACHINE DRIVING DEVICEWilliam H. Brady, Roselle, N. J., assigner to The Singer ManufacturingCompany, Elizabeth, N. J., a corporation of New Jersey Application April13, 1935, Serial No. 16,129

6 Claims.

This invention relates to electric driving devices for small machinesand has for an object to provide simplified, inexpensive and practicalmeans for effecting the electrication of a small machine andparticularly a small, inexpensive, handdriven type of sewing machine,such as has been designed for childrens use.

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

In the accompanying drawings Fig. 1 is a top plan view, partly insection, of la motor-driven sewing machine embodying the invention. Fig.2 is a right end elevation of the driving device as applied to thesewing machine. Fig. 3 is a fragmentary front elevation of the machine.Fig. 4 is a fragmentary rear elevation of the machine, and Fig. 5 is asection on the line 5 5, Fig. 2.

I represents the pedestal of a sewing machine having a base 2 andcarrying the cloth-plate 3 and standard 4 of the usual bracket-arm (notshown) which carries the reciprocatory needle 5 and presser-foot 6cooperating, respectively, with the rotary looper 1 and feed-dog 8.

The looper 'I is mounted on one end of the rotary shaft 9 journaled inbearings IIJ on the pedestal I and having fixed to its opposite end agear-wheel II meshing with the internally toothed balance-wheel I2 whichis journaled on the stud-pin I3 fixed to the bracket-arm standard 4. Thegear-wheel II carries a crank-pin I4 which aetuates the usualneedle-driving pitman I5. The complete sewing machine is mounted on thesheet-metal sub-base I6 by means of the screw I'I. The sewing machineVbase 2 is faced with felt I8 and the sub-base is also faced on its underside with a layer of felt I9 cemented thereto.

Spot-welded or otherwise suitably secured flatwise upon the rearwardend-portion of the subbase is a U-shaped sheet-metal member 2B theupstanding legs 2l of which are apertured at 22 to receive theinternally threaded fulcrum bushings 23 secured onto the ends of thetie-rod 24 which together with the tiebolt 25 hold together the twosections 26 of the frame of the conventional motor M. The motor M has apower shaft 2l which carries a double grou-ved belt-pulley 28.

Screwed rigidly to the motor frame is the control arm 29 to. which isfixed the laterally extending bearing stud 30 for the bushing 3|carrying the double grooved belt-pulley 32 and rubber driving wheel 33arranged to bear upwardly upon the rim of the sewing machinebalanceewheel I2. '"5 A spring 34 coiled about one of the motor-iulcrumbushings 23 and reacting oppositely against the sub-base I G and arm 29,yieldingly urges the arm 29 and motor M in a direction to carry thedriving wheel 33 into driving relation with the balancel0 wheel I2.

The arm 29 has a forwardly extending portion afording a finger-piece 35which is provided with a clearance aperture 36 for the upwardlyextending push-button 3l of a conventional single-pole 15 push-onpush-off switch 38, connected in the motor circuit to start and stop themotor M. Switches of the type in question are disclosed in U. S. PatentsNo. 729,772, of June 2, 1903, and No. 1,542,154, of June 16, 1925. Theswitch 38 20 is of the single-hole mounting type having the threadedstem 39 and nut 4l). It is mounted in the apertured top plate 4I ofV asheetmetal switch-housing 42 formed in one piece with the sheet-metalangle-bracket 43 which is spot- 25 welded atwise upon the sub-base I 5.The switch support or housing 42 thus overhangs but is entirely clear ofthe sewing machine base 2 and does not interfere with the attachment ofthe sewing machine to the sub-base I6. A nger- 30 guard 44 isspot-welded to the switch housing and has an ear 45 which may be securedby the screw 46 to the standard 4.

The operating arm 29 has a downward branch 4l which functions as a stopby engagement with 35 the base 2 when the ringer-piece 35 is depressed.The pulleys 28 and 32 are connected by a live rubber round belt 48. Thepulley sizes are so chosen that two different reduced speeds of therubber driving wheel 33 may be obtained from 40 a motor having aconstant speed.

The operation is as followsz-With the motor M at rest and the parts intheir full-line positions, Fig. 2, the operator pushes downwardly uponthe switch button 3l and simultaneously de- 45 presses the lever 35 thusdisconnecting the friction pulley 33 from the sewing machinebalancewheel. The motor M is thus free to start under no load at themoment the starting switch 38 is closed. After the motor has beenstarted, the op- 50 erator allows the linger-piece 35 to rise under theforce of the spring 34, whereupon the pulley 33 is caused tofrictionally engage the balancewheel I2 and drive the sewing machine.

The linger-piece 35 has a fiat portion 48 in rear 55 of the slottedportion, upon which the operator may press to disconnect the pulley 33from the balance-wheel l2 without pushing the switch button 31 to stopthe motor. Alternatively, the operator may stop the motor by pushingdownwardly upon the switch-button 31.

I'hese provisions permit the use of a smaller and less expensive motorthan would be required in cases where the motor is started under load.Furthermore, in the present outt, no rheostat or speed-regulating deviceis required other than the arm 29 which may be depressed to regulate themachine speed by regulating the slippage between the friction pulley 33and balance-wheel l2.

Having thus set forth the nature of the invention, what I claim hereinistl. The combination with a machine having a balance-wheel, of meansfor driving said balancewheel including an electric motor and a frictionpulley driven by said motor and, in the absense of attention by theoperator, spring-biased against said balance-wheel, and devices movablesimultaneously in the same direction by one and the same motion of theoperators hand to start the motor and disengage said friction pulleyfrom the machine balance-wheel.

2. The combination with a machine having a balance-wheel, of means fordriving said balance-wheel including an electric motor and a frictionpulley driven by said motor and, in the absence of attention by theoperator, springbiased against said balance-wheel, and devices movablesimultaneously in the same direction by one and the same motion of theoperators hand to start the motor and disengage said friction pulleyfrom the machine balance-wheel, said devices comprising an electricpush-button switch connected in the motor-supply circuit and acontrolling arm for shifting said friction pulley, said controlling armhaving a finger-piece disposed closely adjacent the push-button of saidswitch and movable independently of and in the saine direction as saidpush-button.

3. The combination with a machine having a balance-Wheel, of aspring-biased electric motor having a friction pulley normally engagingthe rim of said balance-wheel without attention by the operator, anoperating arm movable downwardly to disengage said friction pulley fromsaid balance-wheel, said operating arm having a iinger-piece disposedforwardly of the machine, and a push-button switch connected in themotorsupply circuit and disposed with its push-button closely adjacentsaid finger-piece and movable downwardly simultaneously with the latterby one and the same motion of the operators nger.

4. In combination, a sub-base, an electric motor mounted on saidsub-base, said sub-base having sucient space in front of the motor forreception of the base of a sewing machine, an operating arm extendingforwardly above said sub-base from said motor to a point in front ofsaid sewing machine receiving space, a friction pulley mounted on saidarm in position to bear upon the rim ofY the balance-wheel of a sewingmachine seated on said sub-base, and a belt-connection between saidmotor and friction pulley.

5. In combination, a sheet-metal sub-base having a sewing machine basereceiving space and motor-supporting` ears rising from said sub-base inrear of said space, an electric motor pivotally carried by said ears, anoperating arm secured to said motor and extending forwardly above saidsub-base to a point in front of said sewing machine base receivingspace, a friction pulley mounted on said arm in position to bearupwardly against the rim of the balance-wheel of a sewing machine seatedupon said sub-base, a belt connection between said motor and frictionpulley, and an electric push-button switch connected to said motor andcarried by said sub-base, said switch being disposed closely adjacentthe free end of said operating arm.

6. Means for the electriiication of a small machine, such as a sewingmachine, comprising, a fiat base-plate having an electric motorpivotally mounted thereon, said base-plate having a surface in front ofsaid motor of sufficient extent to receive the base of a smallconventional machine to be seated thereon and fastened thereto, anoperating arm xedly secured to said motor and overhanging saidbase-plate, said arm terminating at its free end in an aperturedfingerpiece above said base-plate, a machine driving friction pulleymounted on said arm and connected to be driven by said motor, a springfor biasing said motor and arm upwardly around the motor pivot, and anelectric push-button switch connected in the motor circuit and havingits push-button in register with the aperture in the finger-piece ofsaid operating arm.

WILLIAM H. BRADY.

